As Engerling (from medium - or Old High German engerlinc / engerinc or engiring = small worm, maggot ) is defined as the beetle larvae of the superfamily Scarabaeoidea (Scarab Beetle). The most famous beetle species are not only the May and June beetles , but also include a. also the garden leaf beetles , rose beetles and rhinoceros beetles .
Beneficial insects, legal protection
While the larvae of May, June and garden tree beetles are considered pests , the larvae of rose and rhinoceros beetles are beneficial insects , which are very valuable in compost heaps and are also "specially protected" species according to the Federal Species Protection Ordinance. According to Federal Nature Conservation Act , it is forbidden “to catch, injure or kill them or to take their forms of development from nature, damage or destroy them”. In addition, their “breeding or resting places” must not be damaged or destroyed; it is also prohibited to buy, sell, or possess them.
May and June beetle larvae are about the same thickness in front and behind, and on the head they have very long, strong legs with clearly developed "kinks". They reach a length of 5–7 cm and are practically never found in compost. Cockchafer grubs hatch from the egg after four to six weeks and become five to six centimeters long. The body is more whitish, whereas the head is brown. Depending on the species, they live in the earth for between two and four years. First they feed on humus , then on delicate grass and herb roots (e.g. dandelion roots) and later also on tree roots. In extreme cases, root damage can lead to the death of fully grown beeches . Because of the nutrition of living plant roots, compost is a completely unsuitable habitat for this species. When the summer weather is favorable , the cockchafer grub pupates and becomes a beetle after four to six weeks . In this form it hibernates in a cave in the ground and, depending on the weather, digs itself out of the ground in April to May of the following year.
Rose beetle larvae ( Cetonia aurata ) are slightly thicker at the back than at the front, have only small stumpy legs, are typically found in compost and are often wrongly killed for fear of plant damage. They feed on rotting wood and plant material and are very useful and valuable in compost due to the accelerated decomposition that this entails.
The larvae of the rhinoceros beetle ( Oryctes nasicornis ) are very large. They grow to be about 7 cm, often even larger.
- Protection status and taxon information rose beetles. Federal Agency for Nature Conservation, accessed on March 2, 2015 .
- cockchafer, grubs and relatives, section grubs. Retrieved March 2, 2015 .